Dishwasher with variable flow rate valve

ABSTRACT

A dishwasher for treating dishes according to an automatic cycle of operation having a tub, a dish holder, a sprayer, a conduit coupled to the sprayer, a pump, and a variable flow rate valve fluidly coupling the pump to the conduits for supplying liquid to the sprayer during the automatic cycle of operation.

BACKGROUND OF THE INVENTION

Dishwashers can include one or more sprayers for providing liquid to the dishes in the treating chamber according to a cycle of operation. The one or more sprayers may be supplied with liquid from a recirculation pump, which draws liquid from the treating chamber. The spray emitted by the sprayers may impact the structure(s) forming the treating chamber and create noise, which may be heard exteriorly of the dishwasher. The operation of the pump motor also generates noise that may be heard exteriorly of the dishwasher. The impact of the emitted spray and the pump are two of the primary sources of noises for a dishwasher during the cycle of operation.

SUMMARY OF THE INVENTION

The invention relates to a dishwasher for treating dishes according to an automatic cycle of operation, having a tub; a first sprayer; a first conduit fluidly coupled to the first sprayer; a single-speed pump having an outlet and an inlet; a variable flow rate valve fluidly coupling the pump outlet to the first conduit; and a controller configured to control the flow rate of the variable flow rate valve according to the automatic cycle of operation.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic, cross-sectional view of an automatic dishwasher according to an embodiment of the invention.

FIG. 2 is a schematic view of a controller of the dishwasher of FIG. 1

FIGS. 3A and 3B are schematic side and top views of the variable flow rate valve in the dishwasher of FIG. 1, respectively wherein a pump outlet is fully aligned with a supply conduit.

FIGS. 4A and 4B are schematic side and top views of the variable flow rate valve in the dishwasher of FIG. 1, respectively, wherein the pump outlet is partially aligned with the supply conduit.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In FIG. 1, an automated dishwasher 10 according to a first embodiment is illustrated. The dishwasher 10 shares many features of a conventional automated dishwasher, which will not be described in detail herein except as necessary for a complete understanding of the invention. A chassis 12 may define an interior of the dishwasher 10 and may include a frame, with or without panels mounted to the frame. An open-faced tub 14 may be provided within the chassis 12 and may at least partially define a treating chamber 16, having an open face, for washing dishes. A door assembly 18 may be movably mounted to the dishwasher 10 for movement between opened and closed positions to selectively open and close the open face of the tub 14. Thus, the door assembly provides accessibility to the treating chamber 16 for the loading and unloading of dishes or other washable items.

It should be appreciated that the door assembly 18 may be secured to the lower front edge of the chassis 12 or to the lower front edge of the tub 14 via a hinge assembly (not shown) configured to pivot the door assembly 18. When the door assembly 18 is closed, user access to the treating chamber 16 may be prevented, whereas user access to the treating chamber 16 may be permitted when the door assembly 18 is open.

Dish holders, illustrated in the form of upper and lower dish racks 26, 28, are located within the treating chamber 16 and receive dishes for washing. The upper and lower racks 26, 28 are typically mounted for slidable movement in and out of the treating chamber 16 for ease of loading and unloading. Other dish holders may be provided, such as a silverware basket. As used in this description, the term “dish(es)” is intended to be generic to any item, single or plural, that may be treated in the dishwasher 10, including, without limitation, dishes, plates, pots, bowls, pans, glassware, and silverware.

A spray system is provided for spraying liquid in the treating chamber 16 and is provided in the form of a first lower spray assembly 34, a second lower spray assembly 36, a rotating mid-level spray arm assembly 38, and/or an upper spray arm assembly 40. Upper spray arm assembly 40, mid-level rotatable spray arm assembly 38 and first lower spray assembly 34 are located, respectively, above the upper rack 26, beneath the upper rack 26, and beneath the lower rack 28 and are illustrated as rotating spray arms. The second lower spray assembly 36 is illustrated as being located adjacent the lower rack 28 toward the rear of the treating chamber 16. The second lower spray assembly 36 is illustrated as including a vertically oriented distribution header or spray manifold 44. Such a spray manifold is set forth in detail in U.S. Pat. No. 7,594,513, issued Sep. 29, 2009, and titled “Multiple Wash Zone Dishwasher,” which is incorporated herein by reference in its entirety.

A recirculation system is provided for recirculating liquid from the treating chamber 16 to the spray system. The recirculation system may include a sump 30 and a pump assembly 31. The sump 30 collects the liquid sprayed in the treating chamber 16 and may be formed by a sloped or recessed portion of a bottom wall of the tub 14. The pump assembly 31 may include both a drain pump 32 and a recirculation pump 33. The drain pump 32 may draw liquid from the sump 30 and pump the liquid out of the dishwasher 10 to a household drain line (not shown). The recirculation pump 33 may include a pump inlet 47 and a pump outlet 45. The recirculation pump 33 may draw liquid from the sump 30 through the pump inlet 47 provided to the recirculation pump 33. The liquid may be simultaneously or selectively pumped through the pump outlet 45 and a supply conduit 49 to each of the assemblies 34, 36, 38, 40 for selective spraying. While the recirculation pump 33 may be a variable-speed pump, the recirculation pump 33 may also be a single-speed pump. For example, the recirculation pump 33 may be the single-speed pump having a single-phase motor, such as a synchronous motor. While not shown, a liquid supply system may include a water supply conduit coupled with a household water supply for supplying water to the treating chamber 16.

A variable flow rate valve 70 may be provided for controlling the flow rate of liquid drawn from the recirculation pump 33. As illustrated, the variable flow rate valve 70 may be fluidly coupled to the pump outlet 45 for receiving liquid drawn from the recirculation pump 46. The variable flow rate valve 70 may also be fluidly coupled to the supply conduit 49 for selectively diverting liquid to at least one of the multiple liquid circuits in the recirculation flow path, such as the upper, mid-level, first lower spray assemblies 40, 38, 34 and second lower spray assembly 36.

For purposes of the invention, the variable flow rate valve 70 may be of any suitable type of valve where the flow rate through the valve may be varied. Non-limiting examples of suitable valves include: ball valve, plug valve, and butterfly valve. For example, the movement of the disk relative to the conduit in the butterfly valve may modify the flow rate of liquid for selectively increasing or decreasing the flow rate of liquid in the liquid circuit, and may be construed to be the variable flow rate valve. While not used as a variable flow rate valve, it is also contemplated that a traditional disk valve may be controlled in such a manner to function as a variable flow rate valve.

A heating system including a heater 46 may be located within or near the sump 30 for heating liquid contained in the sump 30.

A controller 50 may also be included in the dishwasher 10, which may be operably coupled with various components of the dishwasher 10 to implement a cycle of operation. The controller 50 may be located within the door 18 as illustrated, or it may alternatively be located somewhere within the chassis 12. The controller 50 may also be operably coupled with a control panel or user interface 56 for receiving user-selected inputs and communicating information to the user. The user interface 56 may include operational controls such as dials, lights, switches, and displays enabling a user to input commands, such as a cycle of operation, to the controller 50 and receive information.

As illustrated schematically in FIG. 2, the controller 50 may be coupled with the heater 46 for heating the wash liquid during a cycle of operation, the drain pump 32 for draining liquid from the treating chamber 16, and the recirculation pump 33 for recirculating the wash liquid during the cycle of operation. The controller 50 may also be coupled with the variable flow rate valve 70 for controlling the liquid flow to the spray system. The controller 50 may be provided with a memory 52 and a central processing unit (CPU) 53. The memory 52 may be used for storing control software that may be executed by the CPU 53 in completing a cycle of operation using the dishwasher 10 and any additional software. For example, the memory 52 may store one or more pre-programmed cycles of operation that may be selected by a user and completed by the dishwasher 10. The controller 50 may also receive input from one or more sensors 58. Non-limiting examples of sensors that may be communicably coupled with the controller 50 include a temperature sensor and a turbidity sensor to determine the soil load associated with a selected grouping of dishes, such as the dishes associated with a particular area of the treating chamber.

During a cycle of operation, some dishwashers may generate noise. The noise may be from the recirculation pump having a motor for running the pump. The noise level of the pump is usually a function of motor speed, such that when the motor speed increases, the noise level typically goes up. Another source of the noise may be a wash noise, generated from the pressurized liquid sprayed on the dishes, racks or other portions of the treating chamber 20. The noise level associated with the sprayed liquid is typically a function of the flow rate of the sprayed liquid. Therefore, one may control the noise generated by the motor by lowering the speed. The lowering of the motor speed results in less fluid flow rate, which, while beneficial in reducing noise, results in less flow rate, which leads to reduced cleaning performance as the sprayed liquid impacts the dishes with less force. Thus, all else being equal, there is a tradeoff between noise and cleaning performance in terms of pump speed. It is possible to compensate some for the tradeoff by running the pump at a slower speed when low soil levels are detected or at known phases in the wash cycle where low soil levels are expected, such as during the rinse phase as compared to the wash phase. However, such a solution requires a variable speed pump, which while desirable in the flexibility they provide for noise control, variable speed pumps are not desirable in that they are more costly compared to fixed speed pumps. Embodiments of the invention take a different approach in that they use a fixed speed pump, which is more cost effective, and control the flow rate of the liquid by a variable flow rate valve 70 to obtain lower flow rates and thus less noise, when it is permissible in the cycle to have lower flow rates. This approach is additionally advantageous in that it permits a lower cost, fixed-speed motor to be used, instead of a higher cost, variable speed motor, for controlling liquid flow rates.

FIGS. 3A-4B illustrate one implementation of the invention where the variable flow rate valve 70 is illustrated as a rotatable disk 71. The rotatable disk 71 includes one or more openings 76, and may rotate to one of the multiple positions about rotational axis 81. In one embodiment, the rotatable disk 71 may be rotatably driven by the valve drive system, such as a drive shaft coupling rotatable disk 71 to a drive motor, such as a stepper motor (not shown). A stationary disk 80 having one or more of the fluid passages 78 may be provided to couple the rotatable disk 71 to the supply conduit 49. As illustrated, the stationary disk 80 may be provided to the top portion of the rotatable disk 71 for selectively aligning the fluid passage 78 to the opening 76. The bottom portion of the rotatable disk 71 may be fluidly coupled to the outlet 45, which may receive liquid drawn from the sump 30 through the recirculation pump 33. While, as illustrated, the stationary disk 80 may couple the rotatable disk 71 to the supply conduit 49, it is also understood that the rotatable disk 71 may be directly coupled to the supply conduit 49 in another embodiment, without the stationary disk 80 in between.

While only one opening 76 and one passage 78 are illustrated, it may be understood that one or more openings 76 may be controllably aligned to one or more fluid passages 78 for selectively diverting the liquid to at least one of the upper, mid-level, first lower spray assemblies 40, 38, 34 and second lower spray assembly 36 at the same time.

For the sake of clarification, the alignment status between the fluid passage 78 and the opening 76 may be represented by the term “degree of alignment.” When the fluid passage 78 is fully aligned with the opening 76, as seen in FIGS. 3A and 3B, it may be referred that the degree of alignment is “fully aligned” and quantified as a numerical reference value, such as 1, or any other accepted value. When the fluid passage 78 and the opening 76 are partially aligned to each other, as seen in FIGS. 4A and 4B, the degree of alignment may be referred to as “partially aligned” and have a numerical value smaller than the reference value. Conveniently, the reference value may be equated with 100% when fully aligned and the corresponding partial alignment is proportional to the percentage of alignment, such as 70%, for example. In such an example, the reference value could be 1 and the partial alignment value could be 0.7. When the fluid passage 78 and the opening 76 are completely misaligned such that no liquid is allowed to flow in either direction, it may be referred that the degree of alignment is zero.

The degree of alignment may be controlled to be close to one, when a cycle of operation requires high flow rate liquid, which is often desired when spraying heavily soiled dishes. While effective in removing soils off of the dishes, high flow rate liquid may not be favorable in that it generates high noise level during the spray of high flow rate liquid in the tub 18, which may lead to the user dissatisfaction.

The degree of alignment may also be controlled to be between zero and one, when the dishes need not be provided with high flow rate liquid. For example, when the dishes are not heavily soiled, moderate flow rate liquid may be enough for treating dishes. In another example, low flow rate liquid may be provided during the rinsing step for rinsing the dishes, following the washing step.

As illustrated in FIGS. 3A and 3B, wherein the degree of alignment is substantially one, liquid supplied from the pump outlet 45 may pass the opening 76 and the fluid passage 78 without any blockage. As a result, the flow rate of liquid passing though the opening 76 and the fluid passage 78 may be maintained at maximum level, and the liquid may generate high level of noise.

Regarding FIGS. 4A and 4B, side and top views of the variable flow rate valve 70 are illustrated, respectively, wherein the pump outlet 45 is partially aligned with the supply conduit 49 to have the degree of alignment set between zero and one.

Depending on the flow rate requirement, the rotatable disk 71 may be rotated by a predetermined degree about a rotational axis 81 such that the opening 76 and the fluid passage 78 may have a predetermined degree of alignment set between zero and one, where the flow rate of liquid passing through the liquid passage 78 may be limited.

With limited flow rate of liquid passing through the supply conduit 49, the flow rate of liquid sprayed from one of the spray assemblies 34, 36, 38, 40 will correspondingly reduce, which will result in a corresponding reduction in the noise generated from the sprayed liquid as it impacts the dishes and the structure, tub and door, forming the treating chamber 20. It is possible to control the flow rate such that the reduced noise will be at a level desired by the end user.

It is further possible to selectively control the flow rate to control the overall noise of the dishwasher during the different phases of the cycle of operation. For example, during a water supply phase, which is known to generate additional noise, it is possible to partially align the rotatable disk 71 so as to reduce the noise from the sprayed liquid to partially or fully offset the noise generated by the supplied liquid. As the cycle of operation is controlled by the controller, the controller may contain instructions and executable logic in its memory as to when to take action to reduce the noise by controlling the alignment, as well as how much misalignment is desired for a given phase of operation.

The invention addresses the problem by controlling an alignment between the openings in the variable flow rate valve and the fluid passages coupled to the conduit to control the flow rate of the liquid, and the corresponding noise level, while using a low cost, single-speed pump. The use of the single-speed pump having the single-speed motor reduces the cost of the pump assembly, which is a relatively large cost item for dishwasher. Unfortunately, the single speed pump does not provide for varying the pump speed, which varies the pressure and the force of the liquid emitted by the sprayer, which prevents using the pump speed as a tool for controlling total noise of the dishwasher. However, the addition of the variable flow rate valve with the single-speed pump provides for the ability to use the pump/valve system as a tool to control the total noise of the appliance, without the expense of a variable speed pump, during the operation of the dishwasher.

The invention described herein provides methods for controlling the noise generated from the dishwasher during a cycle of operation by controlling the flow rate of liquid flowing though the variable flow rate valve 70, while using the low cost, single-speed pump. The noise from the liquid sprayed in the treating chamber may be controlled by controlling the flow rate of liquid by the variable flow rate valve 70. The use of the single-speed pump may be advantageous in that the single-speed pump is generally more cost effective than the variable speed pump.

While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims. 

What is claimed is:
 1. A dishwasher for treating dishes according to an automatic cycle of operation, the dishwasher comprising: a tub at least partially defining a treating chamber for receiving dishes for treatment; a first sprayer for spraying liquid in the treating chamber; a first conduit fluidly coupled to the first sprayer and through which liquid may be supplied to the first sprayer; a single-speed pump having an outlet and an inlet, with the inlet being fluidly coupled to the treating chamber; a variable flow rate valve fluidly coupling the pump outlet to the first conduit; and a controller configured to control the flow rate of the variable flow rate valve according to the automatic cycle of operation.
 2. The dishwasher of claim 1 further comprising a second sprayer and a second conduit fluidly coupled to the second sprayer, with the variable flow rate valve being selectively coupled to one of the first and second conduits, with the controller configured to control the flow rate of the variable flow rate valve according to the selected one of the first and second sprayers.
 3. The dishwasher of claim 1 wherein the single-speed pump comprises a single-phase motor.
 4. The dishwasher of claim 3 wherein the single-phase motor comprises a synchronous motor.
 5. The dishwasher of claim 1 wherein the variable flow rate valve comprises a diverter valve selectively fluidly coupling the pump outlet to an inlet of the first conduit.
 6. The dishwasher of claim 5 wherein the diverter valve comprises a rotatable disk having at least one opening that may be aligned with the first conduit inlet to fluidly couple the pump to the first sprayer, wherein a degree of alignment of the opening with the first conduit inlet is controlled by the controller to control the flow rate through the diverter valve.
 7. The dishwasher of claim 6 wherein the degree of alignment is a function of the noise generated by the pump during the cycle of operation.
 8. A method of treating dishes according to an automatic cycle of operation in a dishwasher having a tub at least partially defining a treating chamber, the method comprising: spraying liquid into the treating chamber through a first sprayer; pumping the sprayed liquid from the treating chamber back to the first sprayer with a single-speed pump; and controlling the flow rate of the liquid from the single-speed pump to the first sprayer according to the automatic cycle of operation by passing the liquid through a variable flow rate valve and setting the flow rate based on the cycle of operation.
 9. The method of claim 8 wherein the controlling the flow rate of the liquid comprises controlling the flow rate of the liquid through the variable flow rate valve.
 10. The method of claim 9 wherein the controlling the flow rate of the liquid comprises controlling a degree of alignment of an outlet of the variable flow rate valve with an inlet to a supply conduit supplying liquid to the first sprayer.
 11. The method of claim 8 wherein the setting the flow rate based on the cycle of operation comprises setting the flow rate based on a degree of soil in the liquid.
 12. The method of claim 8 wherein the setting the flow rate based on the cycle of operation comprises setting the degree of alignment of an outlet of the valve with an inlet to a supply conduit based on the cycle of operation.
 13. The method of claim 8 further comprising pumping the sprayed liquid from the treating chamber back to one of the first sprayer and a second sprayer with the single-speed pump.
 14. The method of claim 8 further comprising selectively coupling the variable flow rate valve to one of the first sprayer and the second sprayer, with the flow rate of the variable flow rate valve controlled according to the selected one of the first and second sprayer. 